Sickle cell disease (SCD) is one of the more common genetic diseases worldwide, affecting approximately 1 in 500 African-Americans and 1 in 1000 Hispanic-Americans. A single amino acid substitution decreases the solubility of deoxygenated hemoglobin, leading to polymer formation and subsequent distortion of erythrocyte shape from the normal biconcave disc into a relatively rigid crescent or sickle shape. Initially reversible, the polymer formation and shape distortion eventually becomes permanent. Clinical manifestations of sickle cell disease relate both to increased clearance of these misshapen erythrocytes (causing a chronic hemolytic anemia) as well as occlusion of small (and sometimes large) blood vessels.